Add Java traces to non-control Rascal exceptions

* Remove unnecessary hiding of exception details from ControlException.
* Make Throw fill in the stack trace.
* ControlException and its other subclasses still skip filling in the
  stack trace.

(Note that the methods dealing with stack traces in the Java library
will always use a special "empty trace" if the stack trace hasn't
been filled in, so printStackTrace() etc should work nicely by
default.)